August 2007

Second quarter 2007 financial results announcement and conference call

The management of Mobile TeleSystems (MTS) will be holding a conference call to discuss the Company’s Second Quarter 2007 Financial and Operating Results on Tuesday, September 4, 2007.

MTS Announces Subscriber Growth Numbers for July 2007

Moscow, Russian Federation — Mobile TeleSystems OJSC («MTS» — NYSE: MBT), the largest mobile phone operator in Russia and the CIS, announces that its consolidated subscriber base reached 74.99 million users on July 31, 2007.

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